Java 8 map JavaBean sum

 User user = new User("tt",2);
        Map<String,User> userMap = new HashMap<>();
        userMap.put("1",user);
        userMap.put("2",user);
        int sum = userMap.entrySet().stream().mapToInt(value -> value.getValue().getAge()).sum();
        System.out.println("---------------sum >"+sum);